Re: But is this the tip of the iceberg?
But what I wonder is why so much insistence on "only a state can write this"
It's an assessment based on probability. To create something that complex needs a LOT of funding, and putting money in something creates an expectation that there is somewhere a return on investment. There are few entities large enough to risk a large dollop of cash on something that is at best uncertain in the returns category, but governments tend to have less of a problem with that. It's not really their money to start with, and covert ops budgets tend to be free from pesky scrutiny anyway so they can afford to take a punt and hide it with the other skeletons if it doesn't pay off.
I would suggest to be more accurate though: I think the actual statement is that only a state would COMMISSION this - I agree with others on this forum that such expertise is nowadays in private hands, so it's probably a subcontracted job with a boatload of threats to stop people from pulling a Snowden on the project and leaking it. But the complexity suggests state funding.
Biting the hand that feeds IT
